1. Field of the Invention
The present invention relates to agricultural fertilizer applicators; and more particularly, it relates to apparatus for subsoil application of livestock waste in the form of a slurry (that is, a freely flowable mixture of liquids and solids).
2. Background of the Art
Historically, livestock waste, particularly in solid form, has been spread on the surface of the soil by a manure spreader using a flail to fling the material to the rear. A more modem side-discharge spreader also discharges the material on the surface of the soil. The advent of confinement systems for animals which include pits below the confinement area, produces a large amount of animal waste which must be handled and disposed of in a slurry form. Typically, the slurry is pumped into a large tank carried by a wagon, but it is still, for the most part, spread or sprayed on the surface of the soil.
This procedure has, as a principle objection, a strong odor which resides after the waste is spread. More-over, surface-spreading of animal waste creates a hazard with the potential runoff of nitrates into rivers and streams or seeping of the material into ground water. This is objectionable because livestock waste is high in nitrogen, and with increasing concern with the quality of drinking water, this procedure is becoming less and less acceptable.
Various methods have been proposed for depositing the slurry underground. One method is to use a fertilizer knife, such as shown in U.S. Pat. No. 4,592,294, and to weld a large pipe to the rear of the knife to deliver the slurry behind the knife and into the slot cut in the soil by the knife. This leaves a very narrow band of fertilizer having a high concentration of nitrogen.
Another method of subsoil delivery of animal waste employs a standard chisel plow shank with an attached wide cultivator sweep, in an attempt to distribute the slurry further laterally and to avoid the concentration which occurs in the case of a simple fertilizer knife, described above.
This method, however, has not fully overcome the concentration problem, and it presents still another problem-namely, the cultivator sweep unnecessarily tills the soil and may result in burying surface residue. This may be a separate problem, particularly for farmers whose land may have been designated HEL, because there are federal requirements to maintain a certain percentage of crop residue on the surface soil. Both the chisel plow shank (which is a wide shank) and cultivator sweeps are designed to create a plowing action that mixes the soil with the residue, buries a large percentage of the residue, and leaves a furrow behind the shank.
U.S. Pat. No. 5,865,131 shows an agricultural slurry applicator having a frame, the is combination comprising: a coulter mounted to said frame to part the soil and form a slot; a shank assembly adapted to be mounted to said frame behind said coulter and comprising: a shank for forming a slot in the soil behind said coulter; a shin wedge mounted in front of said shank and having a vertical leading edge following in the slot formed by said coulter to widen said slot to a width approximately equal to the width of said shank; a point mounted to the bottom of said shank and extending forwardly thereof; first and second wings mounted behind said point and respectively on either side of said shank each wing having a cutting edge extending outwardly and rearwardly relative to said point, said point and wings cooperating to break the soil in front of said shank and to lift the soil along paths defined by said wings to form fissures without substantial tillage of the soil; and a slurry delivery tube mounted to said shank and extending downwardly in the slot formed by said shank, said delivery tube defining a discharge opening to place slurry immediately behind said shank and adjacent the inboard ends of said fissures formed by said wings, whereby said slurry moves outwardly in said fissures as they are formed by said wings and the soil raised by said wings is free to fall after said wings have passed and said slurry has been placed. The advantage of that construction is the employment of a spring-cushioned coulter running ahead of the applicator for cutting an initial slot in any residue and for providing a break line for the soil to be parted by the trailing shank. The trailing shank, in turn, spreads the initial slot, and deepens it, for the entry of a slurry delivery tube welded behind the shank.
The trend toward reduced-till and no-till farming for soil and water conservation is shown graphically in an article published in the New York Times May 11, 1982, entitled xe2x80x9cErosion Wary Farmers Are Sparing Traditional Plowxe2x80x9d. The necessity for sub-surface application of fertilizers for efficient utilization of plant food, as indicated by research done by TVA""s NFDC, universities, and agriculture experiment stations, has resulted in many proposals for solving this problem. Some of these are outlined in the article entitled xe2x80x9cMaking Fertilizer More Efficientxe2x80x9d in the periodical xe2x80x9cBig Farmerxe2x80x9d, April 1982 edition.
TVA scientists have stated that broadcast application of nitrogen fertilizers on no-till soils can result in losses as high as 40 percent, and the author of the xe2x80x9cBig Farmerxe2x80x9d article states xe2x80x9cEfficiency standards for broadcasting phosphorous range from 10 to 30 percent.xe2x80x9d There is little no doubt that even the most xe2x80x9cbackwardxe2x80x9d farmer is aware of the tremendous increase in cost of fertilizers, and the necessity for its efficient placement, which is bound to result in the adoption of sub-surface application.
Most methods of sub-surface placement in reduced-till or no-till farming involve the use of a cutting coulter running ahead of a knife or chisel plow with a liquid fertilizer application tube extending down the back of the knife or plow. Theoretically this may seem to be a good method, but the development of numerous such applicators since 1952 has proved that this method is not practical for general use. In hard ground it is practically impossible to apply enough force on coulters to keep them in the ground, and even if this can be done (by using only a minimum number) their life is very short because they are subject to bending, breakage and bearing and spindle failures. In soft ground coulters may not cut the trash, but push it below the surface where it will be caught by the applicator blade or chisel plow and tear out wide trenches in the soil. Further, unless the coulter is kept in exact alignment with the applicator blade, trash will wedge between the coulter and the blade, and tear out large chunks of soil. It is practically impossible in normal usage to keep the coulter and knife aligned for any length of time, because driver-operators will nearly always turn the machine to some degree with the tools in the ground.
Jet injection of agricultural liquids into the soil in no-till farming, i.e. without appreciable disturbance of the soil, has been proposed. Among the earliest of these proposals is that disclosed is U.S. Pat. No. Re 25,307, Dec. 25, 1962, which had as its principal object the continuous injection of anhydrous ammonia, at the bottom of a slot cut by a coulter, with a high pressure (e.g., 2000 psi) traveling jet having a velocity of the order of at least 700 feet per second and a fineness of the order of about 0.007 to about 0.050 inch in diameter. Another proposal is that disclosed in Baldwin et al., U.S. Pat. No. 3,012,526, which had as its principal object the successive injection of slugs of agricultural liquids with a high pressure (e.g. 500-1500 psi) traveling intermittent jet having a fineness of 0.080 inch in diameter. For this purpose Baldwin used a high pressure reciprocating pump and a spring-closed valve in the injection nozzle set to open at a predetermined pressure to receive liquid from the pump and create the successive high velocity slugs at the jet nozzle.
Such proposals, however, have not become commercial because of their lack of efficiency in terms of liquid placement or equipment cost and life. The sub-surface placement of a continuous band of liquid along a plant row is impractical because at normal application rates, i.e., gallons per acre, the jet must be so fine that extremely high pressures must be used to achieve sufficient penetrating power. Further, the necessary extremely small nozzle orifice would clog up constantly. Intermittent injection of liquid along a plant row has its advantages over continuous injection in that nozzle size may be increased and the jet accordingly can achieve the same penetrating power as a continuous fine jet with reduced pressure. A larger nozzle also is not so susceptible to clogging.
U.S. Pat. No. 4,624,193 is asserted to provide an improved method and apparatus for high pressure injection of agricultural liquids into the soil without the necessity of any tillage, i.e., disturbance of the soil by mechanical means, which is efficient and economical from the standpoint of both placement of adequate quantities of liquid at the proper subsurface location and cost, life and ease of operation of the apparatus. The foregoing object is attained by the use of a series of jet nozzles, one for each plant row, spaced along the usual tool bar, creating by an appropriate pump a source of liquid under substantially constant high pressure with an adjustable delivery rate proportional to ground speed; and connecting that source successively to the nozzles at a timed rate proportional to ground speed so that the entire output of the pump is concentrated through one nozzle at a time, for a brief interval, e.g., a fraction of a second, to eject a high velocity slug of liquid that will penetrate the soil to an agrinomically satisfactory depth, e.g. 2-6 inches. The timing is such that one slug is injected from each nozzle during a predetermined distance of travel thereof, e.g. 12xe2x80x3, to provide a series of equally spaced injections along each plant row. That invention is accomplished by the use of a timing distributor that concentrates the entire output of an adjustable-delivery-rate high pressure pump through relatively large jet nozzles, one at a time, for only a fraction of a second. This provides the greatest possible jet penetrating power for a given maximum pressure. A continuously flowing small jet nozzle would require 4 to 5 times the pressure for the same jet penetrating power, and the nozzle would have to be so small that it would clog up continuously.
Krumholz U.S. Pat. No. 3,701,327, entitled xe2x80x9cPLANTER AND METHOD OF PREPARING SOILxe2x80x9d, discloses a fertilizer and planter assembly having a single forward-mounted fluted coulter for cultivation and residue removal. The Krunholz patent also includes the coulter and fertilizer elements as parts of a central frame apparatus. The Krumholz patent does not disclose any specific mounting or biasing assembly for the coulter unit in relation to the main frame assembly, nor the use of a dual coulter assembly for increased soil preparation efficiency.
Hardin et al. U.S. Pat. No. 4,187,916, entitled xe2x80x9cSOIL CONDITIONING AND SEED BED PREPARING APPARATUSxe2x80x9d, discloses a main frame assembly having a subsoil trenching blade with following fertilizer delivery tube and a trench filling fluted coulter wheel. Mounted to the front of the main frame by unequal length control arms is a fluted coulter with exposed spring biasing means. On the rear of the main frame is mounted a flex arm on each side of which is mounted a fluted coulter assembly with a variety of adjustment means. The coulter assembly itself contains no biasing spring. The Hardin et al. patent does not disclose the optimal spatial relationship between the offset fluted coulter wheels, but merely indicates that such offset will prevent clogging of the assembly. The Hardin et al. patent further contemplates that a conventional seed planting mechanism will be attached to and pulled behind the entire soil conditioning and seedbed preparation apparatus.
U.S. Pat. No. 4,987,481 describes a preferably uses paired, mirror-image fluted coulter assemblies for each seedbed, having adjustably attached fertilizer delivery tube assemblies which may contain optional knife-blades for additional soil cultivation.
Attachment of the two assemblies to an existing seed planting apparatus is accomplished by unequal length mounting brackets, thus ensuring that the coulter wheels will be longitudinally offset from each other for maximum efficiency. The mounting brackets allow coulter assembly attachment to the front, back, or underside of the front bar of an existing seed planting apparatus to provide a wide variety of placement options for the operator.
The assembly is spring biased towards the ground, and includes a spring housing assembly which may further function to receive the mounting brackets as an attachment point. The assembly may, by variously positioning the spring housing assembly within the adjustable mounting brackets, be adjusted for depth of cultivation. Lateral offset of the paired assemblies may be accomplished by variously and selectively locating the mounting brackets on the seed planting apparatus.
Fertilizer delivery tubes are attached to the apparatus behind the coulter wheels by means of a double-bend linkage arm attached to adjustable brackets. The double-bend linkage arm prevents soil and residue from clogging up in the fertilizer delivery tube area and thereby affecting the operation of the apparatus.
A device to deliver slurry into soil is attached behind a moving vehicle, the device comprising:
a) a hinged connector that allows side-to-side movement (essentially horizontal movement) between the vehicle and b);
b) a main frame;
c) at least one coulter attached to the main frame;
d) a retaining wheel and slurry applicator attached to the main frame; and
e) a closure wheel attached to the main frame.
The at least one coulter preferably comprises a double coulter system and the closure wheel preferably has radially extending fingers. The slurry applicator is positioned to deliver slurry behind or in front of the axis of the retaining wheel. The closure wheel is preferably pivotally attached to the main frame and preferably the coulter is provided with a shock absorbing system between the coulter and the main frame. The retaining wheel is also preferably pivotally attached to the main frame and has tines radially extending from the wheel.